Sir David Bell’s intervention last week was a timely reminder of how much is at stake in education at the election. First, it was a classic piece of New Labour spin, leaked first to a friendly newspaper – The Independent, not the more obvious Guardian – and then plugged in a softly, softly, interview on the Today programme.

What sensible person could disagree with such an expert? We have had too much too soon, gone too far too fast, and much better to leave things as they are – that is, as they were in 2010.

Sir David’s career is a classic example of stealth politics. The only evidence of his party allegiance is his attendance at Blair’s first victory party, reported in the Sunday Times. Thereafter, his career was fostered by Labour ministers and local authorities as he moved from Director of Education at Newcastle, where Secretary of State Charles Clarke blamed poor performance on the parents, to Chief Executive of Bedfordshire, Ofsted Chief Inspector and later “permanent” secretary at what had been the Department for Education.

In the last two posts, he oversaw the merger of education with social services, stripped inspection back so hard that it could no longer identify problems – contributing to both the Haringey scandals and Trojan Horse – and made achievement just one-half of one of five goals for education in Labour’s educational year zero, “Every Child Matters”. The empire is ready to strike back, and Sir David, still a young man in political terms, is staking his claim to a leadership position if and when the time comes.

Labour left us with a system of debased qualifications that had virtually eliminated education from the last four years of school and turned them into one long test. Plenty of teachers have agreed with me privately on this, including one very prominent languages teacher who admitted to using phrasebook techniques just to get pupils through GCSE. Teaching for earlier years was based on a series of steamrollers, designed to centralise thinking, and leaving teachers with no discretion to think about the pupils in front of them.

The early years programme was designed to hold back higher achieving children by keeping them from teaching that they might have benefited from more than others. The national strategies were taken over by people who were at times to the Left of Labour itself, and who sneaked in progressive ideas under the noses ministers who saw themselves as traditionalists.

The most prominent example was the downgrading of phonics in the literacy strategy during the tenure of David Blunkett. It didn’t work – towards the end of their time, the strategies were producing materials to teach the two times table to ten- and eleven-year-olds, oblivious of the fact that the need to do this showed that they were failing.

That, though, did not matter. What mattered was power and control. We were saved – just – from an even more disastrous education act by the timing of the last election.

The rearguard action began straight away. Labour did not like school subjects, and had a policy of putting civil servants in charge of them that did not come from the subject itself, so that they would not go native. Some civil servants did an honest and honourable job, while others did what they could to hold things up and funnel funds to what was left of Labour’s quangos. Examiners and headteachers from the Labour years held up reform. We all, no doubt, remember the examiner who was going to give children credit for telling him to f-off. Labour’s adviser on school discipline, Sir Alan Steer, actually opposed giving heads the right to impose an immediate detention for poor behaviour, and many heads still won’t use it.

We are dealing here with a clash of principles rather than ideology – is the main purpose of a school to promote teaching and learning, as most Conservatives believe, or is it to subordinate this to social inclusion, as in Channel 4’s Educating series? We need, of course, a balance, but I submit that, for us, teaching and learning come first, and are worth more than a passing mention half way down the list.

Similarly, qualifications at all levels should be just that – qualifications. Labour’s approach, stated by Ed Balls as making examinations “more accessible”, and enforced by sending DfE representatives to examining boards, was an exercise in certifying incompetence and semi-literacy. In the context of Ofsted’s ill-informed move to basing inspections on data, it led to widespread fraud and a proliferation of non-qualifications that made the government and headteachers look good at the expense of pupils who tried to base further work on these grades.

I know one student who passed an NVQ in “forensic science”, copied from the internet, who is now happily engaged in a course on painting and decorating. It would have made sense to give him this option in the first place.

In short, a Labour victory would have the same consequences for education that David Cameron and George Osborne have described for the economy. Ruin. We must do all we can to prevent it.